In this article, we are concerned with the existence of positive solutions for nonlinear fractional differential equation whose nonlinearity contains the first-order derivative,
$$\displaylines{
D_{0^+}^{\alpha}u(t)+ ...

In natural logic, the goal is to create a system of logic that is as sim-
ilar to natural language as possible. In order to build a natural logic,
simple sentence forms are considered, slowly incorporating more ...

We introduce systems of objects and operators in linear monoidal categories called $\hat{\Psi}$-systems. A $\hat{\Psi}$-system satisfying several additional assumptions gives rise to a topological invariant of triples (a ...